1. Field of the Invention
The present invention is directed to a system that combines a pen digitizer into a notepad (or notebook) type computer and, more particularly, providing such a system by nesting the digitizer in the display and within the thickness and area of a traditional notepad (or notebook) and providing a pen/paper feel while improving the quality of the image displayed.
2. Description of the Related Art
Typical pen-based computers include a tablet-type pen digitizer technology which is used for input. Combining the tablet technology into a notepad or notebook type computer will result in a thick and heavy device making it difficult for such a device to be perceived as a true notepad type device. Other portable, pen-based input devices do not function as computers but rather as limited input devices. What is needed is a notepad computer that integrates the technology for pen based input into the display, without creating a heavy or thick device.
The display area of a pen-based computer over which the input with a pen is permitted is substantially smaller than the surface area of the device because regions on the edge of the input field are needed for input circuits and electronics. What is needed is a system that maximizes the input field size relative to the extent of the top surface of the notepad device.
Displays that use liquid crystal technology are prone to distortions in the image when a user contacts a pen or finger to the display surface. This creates visual distractions while using the device. What is needed is a system that prevents such distortion without preventing such contact.
Users of pen-based input devices also need to become accustomed to the tactile feel of the device as the input pen is moved across the surface. This feel is substantially different from the feel of a pen against paper. What is needed is a system in which users immediately feel they are using a familiar surface.
Electronic information systems capable of emulating pen and paper would have tremendous advantages in usability over traditional computers, with which interaction is much less intuitive and less direct.
Electromagnetic pen technology is the most capable of providing the desired input performance (accuracy, stability, and expressiveness), and liquid crystal displays are the most capable of providing the desired output performance (high resolution, brightness, contrast, and color depth, with small size, weight, and power consumption). However, attempts to date at using the technologies together have resulted in compromising all of these qualities.
Specifically, all pre-existing techniques for integrating electromagnetic pen and liquid crystal display (LCD) technologies have suffered from: 1. Inaccuracies, instabilities and/or parallax that make it impossible for the tip of the pen to provide a true representation of where ink will appear, as it does with pen and paper; 2. Susceptibility to electromagnetic interference that contributes to the inaccuracies, especially when the sensor is integrated tightly with system electronics; 3. Compromises to the optical characteristics of the displayed image due to losses in brightness and contrast from additional optical layers and surface reflections; and 4. Compromises to the size and weight of the system.
What is needed is a means of integrating electromagnetic pen and liquid crystal display technologies in a way that avoids compromising the performance of each.
It is an object of the present invention to provide a true notepad-type (or notebook) computer that integrates the electronics for pen-based input into the display.
It is a further object of the present invention to integrate electromagnetic pen digitization technology into a display module.
It is another object of the present invention to provide a notepad computer that maximizes the input field size relative to the extent of the front surface of the notepad.
It is a further object of the present invention to provide a system that prevents display distortion caused by touching the display screen.
It is an additional object of the present invention to provide the feel of a pen against paper.
It is also an object of the present invention to provide materials and processing techniques which, when applied to device construction, yield further improvements in pen and display performance and quality.
It is an object of the present invention to provide an electromagnetic pen digitizer construction which achieves high performance input in combination with a thin film transistor (TFT) display.
It is an object of the present invention to provide a system in which the system electronics can be located in close proximity to the display therefore.
The above objects can be attained by a notepad (or notebook) computer that includes a liquid crystal, thin film transistor display with driver lines connected to the transistors and folded around a light pipe and digitizer so as to integrate the digitizer into the notepad computer while maintaining a minimal height and weight. The digitizer has a grid whose conductors connect to routing lines which are routed behind a shield, which is optionally connected to or integrated with additional shields of the computer system electronics, such as the processor. The display electronics and digitizer electronics are mounted inward of an edge of the display keeping the display as narrow as possible. The display layer, which includes the display addressing circuits, has spacer beads whose distribution density, compressibility, and migration are controlled. The glass layers in front of and behind the beads can have different thicknesses and different composition. A surface of the display provides a pen/pencil on paper feel as a digitizer pen is moved across the surface.
These together with other objects and advantages, which will be subsequently apparent, reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.